. >> reporter: a lone traveler allowed to fly in a frightening getup from asia to california. yongda harris' flight suit? fireproof leggings, knee pads, a chinese knockoff bulletproof-style vest, all covered by the stereotypical long black trench coat. >> this guy is involved in some sort of delusion or fantasy that's totally inappropriate, obviously. >> reporter: in fact, sources tell abc news harris, carrying only a laptop, wore that vest through security in china. but was taken aside and questioned during his route through south korea and japan, then allowed to proceed to the united states. when he landed in los angeles, a customs agent noticed the unusual garb, checked his bag and police arrested him. >> he had a myriad of items in his checked-in luggage that raised a lot of suspicion. he had a gas mask, knives, handcuffs. >> reporter: still, it may surprise the average passenger, none of that frightening gear, not even the body bags in his luggage, is banned from planes. only a smoke grenade, also found in his checked luggage, is illegal, and the tsa is investigating how